Herriman would come on board as Bruno Hauptmann, the man convicted of kidnapping and killing the Lindbergh baby. His conviction came into question later because police were accused of manipulating the evidence, though, which prompted Hoover to launch an FBI inquiry into the police handling of the case. Dench's role in the film has yet to be announced.

As you've probably discerned from its title, the film follows the life of the FBI's first director, J. Edgar Hoover, as told from his perspective. DiCaprio is tapped to play the title character, while Hammer will play his protégé and purported lover, Clyde Tolson. Theron was offered the job of Helen Gandy, a Justice Department file clerk who ended up becoming Hoover's personal secretary (for 54 years!), though her role wasn't confirmed when it was announced earlier this month.

The script comes from Oscar-winning "Milk" screenwriter Dustin Lance Black, and Eastwood will direct. If that powerhouse duo and the exciting cast hasn't already got you thrilled for this flick, then maybe the way it's told will.

"People know Hoover -- or think they know Hoover -- and that's great as a writer because you're free as a writer to explore other stuff," Black said earlier this year. "['J. Edgar'] is told from Hoover’s point of view, which I've never seen before. Because of that -- and the contradiction between what he believed his history was and what his history actually was -- it lends itself to a less-traditional structure. There are more contradictions."